Petroleum kerogen

Hydrocarbon mixtures of hundreds of chemical compounds represented by the mineral oils, those contained in geological deposits, e.g., petroleum, kerogen, natural asphalt, etc. 

Oil shale deposits were formed in ancient lakes and seas by the slow deposition of organic and inorganic remains. The geology and composition of the inorganic minerals and organic kerogen components of oil shale vary with deposit locations throughout the world (1) (see also Fuel RESOURCES Petroleum). 

Synthetic fuels derived from shale or coal will have to supplement domestic suppHes from petroleum someday, and aircraft gas turbine fuels producible from these sources have been assessed. Shale-derived fuels can meet current specifications if steps are taken to reduce the nitrogen levels. However, extracting kerogen from shale rock and denitrogenating the jet fuel are energy-intensive steps compared with petroleum refining it has been estimated that shale jet fuel could be produced at about 70% thermal efficiency compared with 95% efficiency for petroleum (25). Such a difference represents much higher cost for a shale product. 

The recovery of petroleum from sandstone and the release of kerogen from oil shale and tar sands both depend strongly on the microstmcture and surface properties of these porous media. The interfacial properties of complex liquid agents—mixtures of polymers and surfactants—are critical to viscosity control in tertiary oil recovery and to the comminution of minerals and coal. The corrosion and wear of mechanical parts are influenced by the composition and stmcture of metal surfaces, as well as by the interaction of lubricants with these surfaces. Microstmcture and surface properties are vitally important to both the performance of electrodes in electrochemical processes and the effectiveness of catalysts. Advances in synthetic chemistry are opening the door to the design of zeolites and layered compounds with tightly specified properties to provide the desired catalytic activity and separation selectivity. 

Petroleum geologists commonly call the catagenesis range, in which oil is effectively produced from kerogen as oil windows . One can see this in Figure 2 in a bell-form generation curve. 

Combined stable isotope analysis ( C, D, N, has been used successfully in petroleum exploration (Stahl 1977 Schoell 1984 Sofer 1984). The isotopic composition of crude oil is mainly determined by the isotopic composition of its source material, more specifically, the type of kerogen and the sedimentary environment in which it has been formed and by its degree of thermal alteration (Tang et al. 2005). Other secondary effects like biodegradation, water washing, and migration distances appear to have only minor effects on its isotopic composition. 

Kerogen - [FUELS, SYNTHETIC - GASEOUS FUELS] (Vol 12) - [PETROLEUM - NOMENCLATURE IN THE PETROLEUM INDUSTRY] (Vol 18) - [OIL SHALE] (Vol 17) -role m petoleum origin [PETROLEUM - ORIGIN OF PETROLEUM] (Vol 18)... 

Hatcher, P. G., E. C. Spiker, N. M. Szeverenyi, and G. E. Maciel. 1983. Selective preservation and origin of petroleum-forming aquatic kerogen. Nature 305 498—501. 

We should caution that the above concept of the genetic relationship between kerogens and asphaltenes differs from the more historic view that asphaltenes are condensation and/or alteration products of hydrocarbons and resins. Certainly, in some petroleum processing treatments and probably at higher maturation levels in nature, various reactions do form new products with asphaltene solubility characteristics. These new condensation products may be regarded as altered asphaltenes and intermediates in the coke or pyrobitumen formation process (62-64)- Contamination of original asphaltenes by subsequently formed or altered products, of course, will result in a less definitive correlation between an asphaltene and its source kerogen. 

Artificial Maturation. Laboratory maturation studies provide a means to determine the influence of temperature on kerogen composition, since other variables (e.g. source input) can be eliminated. In order to study the behaviour of organically bound sulfur under these controlled conditions, Py-GC-FID/FPD was performed on a suite of solvent-extracted residues from sealed vessel (hydrous pyrolysis) experiments aimed at simulating maturation over the range involved in petroleum generation. 

The following organisations are thanked for their kind donation of samples Institute Francais du Petrole, British Petroleum, Norsk Hydro. We are grateful to the analytical departments at Bristol University and at BP Research Centre for the elemental analyses. Dr. A. Pepper (BP) is acknowledged for provision of burial history information for the Monterey Fm. kerogens. ll Buxton (Geolab Nor) is thanked for selected TOC determinations. Dr. J.M. Jones (University of Newcastle) is thanked for vitrinite reflectance analyses. We thank Dr. A.K. Burnham for supplementary kinetic analyses. W. Pool is thanked for technical assistance. Drs. K. Peters, W.L. Orr and C.M. White are thanked for critical reviews. 

Oil shale Sedimentary rock containing kerogen, a high molecular mass hydrocarbon, that is insoluble in common solvents and is not a member of the petroleum family. 

Tar sands are normally a mixture of sand grains, water, and a high-viscosity crude hydrocarbon called bitumen. Unlike kerogen, bitumen is a member of the petroleum family and dissolves in organic solvents. At room temperatures the bitumen is semisolid and cannot be pumped, but at temperatures of about 150°C it will become a thick fluid. In the Alberta deposits of Canada, the bitumen is present in a porous sand matrix in a range up to about 18 mass%, although the sum of bitumen and water generally totals about 17%. 

Kerogen organic matter in rocks in the form of a mineraloid which is of indefinite composition, insoluble in petroleum solvents. 

---